This application is a continuation-in-part of application Ser. No. 927,250 filed July 21, 1978, for Electronic Timepiece.
This invention is directed to a miniature electronic timepiece and, in particular, to a quartz crystal electronic wristwatch capable of providing a timing rate adjustment signal representative of the amount of timing rate adjustment being effected and/or needed to be effected in order to obtain accurate timekeeping.
Heretofore, several methods have been utilized for adjusting the timing rate of an electronic wristwatch in order to obtain improved accuracy. Initially, oscillator circuits were provided with tuning capacitors and other variable impedance elements for permitting the high frequency signal produced thereby to be selectively varied. Thereafter, it was found that more accurate adjustment of the timing rate of the timekeeping circuit could be effected by utilizing an adjustment circuit to continuously apply an adjustment signal to the divider circuit. By this approach, the frequency of the signal, produced by the oscillator circuit, would not be varied. Still further approaches have included the use of at least two high frequency vibrators and a comparator for comparing the frequencies thereof and producing an error signal. Although each of these methods have permitted highly accurate adjustment of the timing rate of the low frequency timekeeping signal without occupying a considerable amount of space, due to increasing current consumption, or substantially increasing the cost of manufacture, such methods have been found to be less than completely satisfactory. Specifically, by using the methods noted above, it is difficult to measure the accuracy of the timing rate and, additionally, it takes a considerable period of time to obtain this type of measurement since the amount of time required for the adjustment signal to be applied to the divider circuit must be taken into account in any measurement that is made.